Milk-derived small extracellular vesicles promote bifidobacteria growth by accelerating carbohydrate metabolism.

Milk-derived small extracellular vesicles (M-sEVs), a critical bioactive component in breast milk, are believed to have an essential role in health, especially in infant development. In early life, bifidobacteria are a dominant genera in the gastrointestinal tract, which can be regulated by specific compounds such as human milk oligosaccharides. However, little is known about the effects of M-sEVs on bifidobacteria. Here, a novel method to generate high-yield M-sEVs was developed and then representative bifidobacteria species were exposed to those M-sEVs. We found that M-sEVs stimulated the growth of bifidobacteria and were absorbed by the bifidobacteria. Different bifidobacteria species responded variously to the M-sEVs. Next, we demonstrated that M-sEVs altered the mRNA profile of B. longum subsp. infantis , and regulated some genes related to carbohydrate metabolism of B. longum subsp. infantis and other bifidobacteria species to accelerate bifidobacteria growth. Overall, the study revealed the supportive effects of M-sEVs on bifidobacteria, and the mechanisms involved. • M-sEVs promote the growth rate of bifidobacteria and increase bacteria numbers of bifidobacteria. • Different bifidobacteria species respond to the M-sEVs variously. • M-sEVs can be uptake by bifidobacteria and regulate genes expression of bifidobacteria. • M-sEVs promote B. longum subsp. infantis growth by accelerating glucose metabolism. [ABSTRACT FROM AUTHOR]